Vehicle wheel construction process

ABSTRACT

An improved process for permanently attaching an overlay to a wheel disc, wherein the overlay is aligned and spaced apart from the wheel disc. A mold is created by a combination of the overlay, wheel disc and localized nests that engage at predetermined times during foam filling to close the mold. The mold is adequately sealed so that there is no foam leakage as the foam expands to fill the mold and, therefore, no final trimming of excess foam is required. The improved process is capable of accommodating a wheel having turbine openings therein.

CROSS-REFERENCES TO RELATED APPLICATIONS

This is a continuation application of U.S. patent application Ser. No.09/855,203, filed on May 14, 2001, which is a divisional application ofU.S. patent application Ser. No. 09/184,190, filed on Nov. 2, 1998, nowU.S. Pat. No. 6,346,159, issued on Feb. 12, 2002.

FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

REFERENCE TO MICROFICHE APPENDIX

Not Applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to composite wheel assemblies for vehicleshaving an overlay permanently attached to a wheel disc with acombination of adhesives and, particularly, to an improved apparatus andprocess for permanently attaching an ornamental overlay to the wheelusing nests to locate and support the overlay to the wheel creating amold into which foam can be injected.

2. Description of the Related Art

Decorative overlays are widely used to enhance the aesthetic appearanceof automotive wheels. Overlays are not only employed to improve theappearance of unadorned standard steel wheels, but are also used withcast aluminum wheels, that are known to be expensive and difficult toplate with chromium. Numerous structural combinations of overlays withchrome-plated outboard surfaces have attracted great interest fromvehicle manufacturers, because they are lightweight, aestheticallypleasing and offer designers complete flexibility with regard to theaesthetic effect that can be created for a specific vehicle regardlessof whether these vehicles use steel or aluminum wheels.

In the past, most overlays were mechanically attached to the wheel. Forexample, Kapanka, U.S. Pat. No. 3,575,468, teaches the use of a springretention device wherein a joined annular wire spring provides aplurality of outer cover-engaging segments adapted to be secured to awheel cover at spaced peripheral portions. A plurality of axial segmentsinterconnect the outer cover engaging segments with outer wheel-engagingsegments adapted to engage a groove in the rim of the wheel. Stay etal., U.S. Pat. No. 4,895,415; Patti, U.S. Pat. No. 4,950,036; as well asHudgins et al., U.S. Pat. No. 5,181,767, teach, alternatively, retentionof the wheel cover by providing wheel cover retaining means forreleasably coupling to at least one lug stud with appropriateconfigurations enabling releasable coupling between the retainer and atleast one stud. German Patent 2,813,412 also mechanically attaches theoverlay to the wheel by utilizing cavities or undercuts in the face ofthe wheel. Further, German Patent 2,848,790 also teaches mechanicalattachment of the wheel cover to the wheel through the use of clamps sothat the cover can be removed for the purpose of cleaning.

Others are adhered to the outboard surface of the wheel, as illustratedby U.S. Pat. No. 3,915,502 to Connell, that teaches an annular-shapedwheel cover that is permanently attached to the wheel with double-sidedadhesive tape. The adhesive tape is positioned midway between the rimand the center hub area of the wheel, while the remainder of the wheelcover is spaced apart from the outboard surface of the wheel. Connellpositions the adhesive tape at radially outward portions of the wheel inorder to avoid the deleterious effects of heat generated by the tire,wheel and brake. While some pressure-sensitive adhesive tapes can beeffectively used in temperatures up to 500° F. (260° C.), the cost ofsuch adhesive tapes is generally prohibitive for use in mass productionapplications such as securing an overlay to a wheel. Consequently, suchapplications are generally limited to the use of less expensive adhesivetapes that have relatively low maximum operating temperatures,necessitating that their placement be restricted to the radially outwardsurfaces of the wheel. Unfortunately, doing so severely limits theadhesive tape's ability to reliably adhere the overlay to the wheel.Further, the use of adhesive tape because of its defined thicknesscreates a void between the overlay and the wheel that can collect dirtand debris that may affect the balance of the wheel.

To avoid such problems, as well as to avoid noise problems associatedwith the use of overlays, the prior art proposes the use of a urethanefoam and a method of permanently attaching a plastic cover to a metalwheel through the use of a urethane foam adhesive, that effectivelyholds the cover in place, closes the void between the overlay and thewheel, and reduces noise as well as provides adequate theft deterrence.This method is best described in U.S. Pat. No. 3,669,501 to Derleth. Theprocess disclosed in Derleth is an annular-shaped overlay composed of athin plastic cover formed from acrylonitrile-butadiene-styrene (ABS)mounted to a wheel spider. The overlay is configured to have variationsin contours in a direction transverse to the axis of the wheel thatexceed the variations in the rim and/or disc contour of the wheel, whichvariations would be extremely difficult and expensive, if notimpossible, to stamp or draw in the disc of the wheel. During assembly,a foamable polyurethane adhesive is coated on the wheel, and the coveris then quickly clamped to the wheel before the polyurethane begins tofoam. As such, the void between the wheel and cover is filled with thepolyurethane foam. However, any excess polyurethane foam formed aroundthe bolt holes or at the periphery of the assembly surrounding the axlehub will squeeze out if appropriate sealing provisions are not made.

One obvious shortcoming of the process disclosed by Derleth is that thecomposite wheel must be imperforate, except for the small bolt openingsnecessary for attaching the wheel to a vehicle. It is understood bythose skilled in the art that it is necessary to avoid the deleteriouseffects of heat generated by the wheel and brake, that cause the ABSplastic overlay to distort, cause delamination of any surface treatment,i.e. paint, plating, etc., and further cause the foam adhesive todegrade, distort and eventually melt. Further problems with urethaneformed wheels surfaced in use. These wheels were very heavy due to thehigh density of the foam and variation in localized density during themanufacturing phase resulted in severe wheel imbalances.

Turbine openings are a necessary element in today's wheel systems inproviding proper cooling to the brake system, not to mention theaesthetics of endless configurations of turbine openings that addindividuality and style to a vehicle. Any opening in the wheel oroverlay using the process disclosed in Derleth is a pathway for the foammixture to escape when it begins to foam and/or cure. Larger openings,such as turbine openings, would not be possible using the Derlethprocess without additional structure to seal the openings to prevent thefoaming material from escaping.

It is appreciated by those skilled in the art that it is advantageous tocompletely fill the cavity with foam adhesive to acoustically dampen anysound produced when the overlay is struck. A drawback of the processaccording to Derleth is that excess foam mixture is required to ensurethat the cavity between the cover and the wheel is completely filledafter the material vents out through the bolt openings. The processdisclosed by Derleth requires any substantial opening in the wheel beplugged or sealed with a sleeve to prevent foam leakage. For example, ifthe wheel hub was left unsealed it would provide a path for some of thefoam to escape, and the security of the cover could be jeopardized.Further, all of the excess foam must be manually removed, which addssignificant cost to the process.

A further disadvantage of the process of Derleth is that thepolyurethane foam adhesive completely breaks down at high temperatures,particularly in the immediate region of the wheel hub where temperaturestend to be much higher than in the remainder of the wheel.

The method according to Derleth has been known since the early 1970'sand due to its many disadvantages has yet to realize practicalapplications and commercial success. The process cannot accommodate theapplication temperature requirements, the need for lighter weightcomponents, and degradation of the urethane adhesive over time, as wellas the need for turbine openings in the outboard face of the wheel.Further, the process is extremely costly due to the labor intensivetrimming operations, difficult process control, environmental, healthand safety concerns.

The teachings of Beam, U.S. Pat. Nos. 5,368,370 and 5,461,779, of a fullsurface curable adhesive are prohibitively expensive and wasteful sincethere is no need for a full surface uniform layer of adhesive to holdthe overlay to the wheel. Further, a full surface uniform layer ofcurable adhesive also detrimentally affects the balancing considerationsof the wheel and overlay assembly.

To avoid the problems of Beam, U.S. Pat. No. 5,597,213 to Chase,assigned to the assignee hereof, teaches the use of an intermediatepositive fixing element for temporarily positioning and securing anoverlay to a wheel during an interval in which a selectively positionedor applied adhesive required to permanently adhere the overlay to thewheel is allowed to cure. The adhesive is selectively placed between theoverlay and the wheel to alleviate concerns of squeaks and rattles aswell as to improve the overall manufacturability, performance andconsumer-perceived quality of the resulting wheel assembly. Therequirement of an intermediate positive fixing element not only addscosts to the overlay but requires careful handling and specialpackaging, all adding to the overall cost of the assembly.

Understandably, what is needed is an economical overlay apparatus andmethod for assembling such overlay to an automotive steel or alloywheel, in which the method promotes the ability to accurately positionand reliably permanently secure the overlay to the wheel by the use ofselective application of a costly curable adhesive in combination with aless expensive foam adhesive so as to improve the manufacturability ofthe wheel, reduce the cost of manufacturing and not detrimentally affectwheel balance or performance.

SUMMARY OF THE INVENTION

The present invention provides a cost effective, highly efficient, safeprocess for permanently attaching an overlay or cladding to a wheel. Thewheel has severe surface variations due to manufacturing tolerances. Inaddition, the overlay has its own surface variations due tomanufacturing tolerances. When the overlay is attached to the wheel,these tolerances are stacked, and could result in an even largervariation. These stacked tolerance variances must be taken intoconsideration during the foaming process. If the variances are notproperly accounted for, one of two things will happen. Either too muchfoam will be injected into the cavity and foam will flash out throughany opening between the wheel and the overlay, as seen in the Derlethprocess, requiring trimming, or not enough foam will be injected intothe cavity resulting in voids and inadequate cover retention. In thepresent invention, a sealant bead is generally applied along the outerperiphery or diameter of the overlay. Optionally, a sealant bead may beapplied around the turbine openings and/or inner diameter or periphery,to provide additional sealing and completely eliminate foam flashing,that in turn eliminates the step of trimming excess foam from anyadjoining surfaces between the cladding and wheel after theadhesive/sealant has cured.

In the present invention, the overlay is aligned with, located, andclamped to the wheel with the exception of predetermined sealed areas.The outboard surfaces of the overlay and wheel are spaced apart, leavinga cavity therebetween. Localized nests at strategically placed locationsact on the wheel and overlay assembly to seal the assembly on the wheeland thereby create a mold cavity. Net standoffs may be used to assistlocating the cover with respect to the wheel and the localized nestsinteract with the overlay and wheel assembly to create a mold cavitybetween the overlay and the wheel into which the liquid foam is injectedand allowed to react to fill the cavity.

A sealant or adhesive can be applied to the overlay prior to assemblingthe overlay to the wheel, depending on the type of wheel that is used tocreate the composite wheel assembly. If an adhesive/sealant is applied,the process begins by fixturing the overlay. In the present inventionthe overlay is oriented with the outboard face down in a nest orfixture. The overlay is located radially off the outside or insidediameter, circumferentially off the valve stem opening or turbineopenings and axially off the outboard surface rim flange area. Vacuummay be applied to the cladding, if necessary, to remove any warpage andassure a truer inboard surface for adhesive or sealant application.Alternatively, the cladding may be fixtured and clamped to ensure thevarious locator datums are maintained. An adhesive/sealant isselectively applied to the cladding at preselected locations dependingon the application. The sealant is applied to the surface of the overlayor the wheel before the cladding is joined to the wheel. Typically, thesealant will be applied to the outer diameter or peripheral edge of theoverlay and, alternatively, as needed, the inner diameter or hub openingas well as surrounding the turbine openings. The adhesive/sealant can beapplied to other areas for additional cladding adhesive strength/sealingor to direct the foam flow pattern. A robotic applicator system is used.

With the cladding appropriately fixtured, as disclosed above, thecladding is located on the wheel. It is preferable to locate axially offthe tire side of the outer wheel flange or rim flange, radially off thetire side rim flange and circumferentially off the turbine openings orvalve stem. The hub bore, bolt circle and other details can also be useddepending on how the wheel is manufactured and the relationship of thedatums to one another and to the overlay. The overlay is located in afixture that locates and processes the cladding to the wheel. Anoptional clamping system is applied to the assembly following preheatingof the assembly. The clamping system consists of temporary clamps, suchas toggle clamps, to hold the overlay to the wheel until furtherprocessing steps are completed. Also, intermediate attachment andlocating features can be used to hold the cladding to the wheel whilethe adhesive/sealant sets, if an adhesive is used.

At this point, if a sealant/adhesive is used, it may require additionalcuring. In such a case, the wheel and overlay assembly is transferred toa curing station, where the sealant/adhesive is allowed to cure.Depending on the type of adhesive/sealant used the curing may involve achemical reaction in case of a two component adhesive, or heat or UVexposure to enhance the reaction and cure time of the adhesive/sealerbefore the clamping system is applied. Further conditioning of theassembly can also take place in the curing station.

After the adhesive/sealant has cured, or if no sealant is used, thewheel and overlay assembly is preheated. The preheating is necessary toraise the surface temperature of the assembly to a defined temperaturethat enhances foam initiation time, adhesion, gel, cohesion, filling,and resultant mechanical properties of the foam.

The preheated assembly is then placed in a filling station that consistsof a clamping fixture having various nests and a foam metering unit. Thewheel and cladding assembly enters the filling station with the wheellocated outboard face down against the inboard side of the cladding andthe pallet on which it travels is engaged by a lower moving platen thatrises and clamps the wheel assembly and associated pallet between thelower and upper platen of the filling station fixture. A first set ofnests, that may be made from a variety of materials depending on theirfunction, engages predetermined areas of the cladding and wheel assemblyfrom the bottom so as to conform to substantially the outboard surfaceof the cladding to support the cladding during the high pressure phaseof the foam filling. A center bottom nest generally conforms to theinside diameter of the cladding and axle shaft opening of the wheel toprovide a seal thereto. Optionally, a second set of nests independentlyseal the various turbine openings allowing independent movement toself-locate to the cladding and wheel. The various nests independentlyengageable, in combination with the steel wheel and cladding create amold in which the foam can be injected. A metering unit is used toaccurately mix and dispense the two component urethane foam. A nozzlemounted to the top clamp platen engages a fill port in the back side ofthe wheel to inject the foamable material in the cladding/wheel assemblycavity. The lower and upper platen clamp is held closed for apredetermined time while the foam flows, gels and thereafter fills thecavity. Thereafter the turbine openings, if used, center bottom andvalve stem nests are disengaged and the lower and upper platen clamp isreleased to allow the pallet containing the cladding and wheel assemblyto be moved to the next station for curing, and eventual removal fromthe fixture. A low out of round point is identified on the wheelassembly before it is shipped.

In summary, the wheel, overlay and selective application of thelocalized nests of the present invention create a sealed mold of thecavity between the wheel and the overlay for the foam to expand in to.The nests and the sealant bead, in combination with the clamping system,provide adequate sealing to prevent foam from escaping through any ofthe openings in the wheel disc. There is no need to add sleeves andcovers, trim away excess foam from the wheel assembly, or clean up anyfoam scrap from the manufacturing equipment and area.

In another embodiment of the present invention, a vacuum can be appliedto the cavity between the overlay and wheel during the foam fillingprocess. Applying the vacuum has a dual purpose of providing additionalholding force between the overlay and the wheel disc to prevent thepressure from separating the two elements, and assisting in filling thecavity, thereby eliminating voids.

It is an object of the present invention to provide an improved methodof permanently attaching a chrome-plated overlay to any wheel disc withan adhesive. The improved process increases process controlcapabilities, improves product quality, and reduces environmental,health and safety concerns.

It is a further object of the present invention to use the improvedprocess to permanently attach an overlay to a wheel having turbineopenings, without the need for labor intensive trimming of excess foam,or the additional structure of sleeves and covers to seal the openings.

It is yet another object of the present invention to create a mold fromthe overlay, wheel, and localized nests that adequately seals any voidsbetween the wheel and overlay and after the application of a sealerallows foam to be injected into the void, permanently attaching theoverlay to the wheel, without the need to trim excess foam.

It is yet another object of the invention to provide an improvedcomposite wheel chrome-plated overlay that utilizes a foamed adhesive incombination with a pre-disposed sealer to attach the chrome-platedoverlay to any type of wheel and to seal all the interfaces between theoverlay and the wheel so as to permanently attach the overlay to thewheel without the need of using excessive foam adhesive that must becleaned from the composite wheel and overlay assembly prior to use on avehicle.

It is yet a further object of the present invention to engage localizednests in predetermined timed sequence that seal the openings in thewheel and overlay assembly while allowing foam to completely fill thevoid between the wheel and overlay without escaping from the openings.

Further features and advantages of the present invention will beapparent from a reading of the detailed description thereof taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded, perspective view of an improved composite vehiclewheel constructed according to the present invention;

FIG. 2A is a side view, partially cutaway, of a vehicle wheel on whichan overlay is adhered in accordance with an embodiment of the presentinvention;

FIG. 2B is a cross-sectional view taken along lines 2B-2B of FIG. 2A;

FIG. 2C is a partial cross-sectional view taken along lines 2C-2C ofFIG. 2A;

FIG. 2D is an alternative embodiment of the vehicle wheel depicted inFIG. 2C;

FIG. 3A is a flow chart depicting the beginning steps of the process ofthe present invention;

FIG. 3B is a continuation of the flow chart of FIG. 3A depicting theremaining steps of the process of the present invention;

FIG. 4 is a partial cross-sectional view of the fixturing of the overlayand wheel assembly in the filling station of the process of theinvention;

FIG. 5 is a schematic representation of the foam filling station of thepresent invention; and

FIG. 6 is a partial cross-sectional view of the contour and lower nestsas well as the secondary clamping system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings, there is illustrated in FIG. 1 anexploded, perspective view of an automobile wheel, indicated generallyat 10, of a prior art drop well fabricated type of wheel 10, andincludes an annular rim 11 and a wheel disc, spider or web 14 thattogether define an outboard surface of the wheel 10. An overlay 13 isattached to the wheel as will be described hereinafter.

Although this invention is discussed in conjunction with the particularwheel disclosed herein, it will be appreciated that the invention may beused in conjunction with other types of wheel constructions. Forexample, the wheel can be a “bead seat attached” wheel (such as shown inFIG. 4 of U.S. Pat. No. 5,188,429 to Heck et al.), a “full faced” wheel(such as shown in FIG. 2 of U.S. Pat. No. 5,595,423, to Heck et al.), a“bimetal” wheel construction including an aluminum disc and a steel rim(such as shown in U.S. Pat. No. 5,421,642 to Wei et al.), or a “modularwheel” construction including a “partial” rim and a full face wheel disc(such as shown in U.S. Pat. No. 5,360,261 to Archibald et al.), all ofwhich patents and others are incorporated herein by reference.

The annular rim 11 is a fabricated rim constructed of steel, aluminum,or other suitable alloy materials. The annular rim 11 includes aninboard tire bead seat retaining flange 16, an inboard tire bead seat18, a generally axially extending well 20, and an outboard tire beadseat 22. The annular rim 11 further includes an opening 19, shown inFIG. 2B, formed therein to accommodate a valve stem (not shown).

The wheel disc 14 is forged, cast, stamped, or otherwise formed, and isconstructed of steel, aluminum, or other suitable alloy materials. Thewheel disc 14 includes a generally centrally located wheel mountingsurface 24, and an outer annular portion 26 shown in FIG. 2B. The wheelmounting surface 24 is provided with a centrally located pilot aperture28, and a plurality of lug bolt receiving holes 30. The lug boltreceiving holes 30 receive lug bolts (not shown) for securing the wheel10 on a vehicle axle (not shown).

The outboard surface of the wheel disc 14 and the outer surface of theannular rim 11 define an outboard or outer surface 32 of the wheel 10,more clearly shown in FIG. 2B. To assemble the wheel 10, the outerannular portion 26 is positioned against an inner surface 21 of the rim11, and a weld 38 is provided to join the wheel disc 14 and annular rim11 together as shown in FIG. 2B. The wheel disc 14 further includes aplurality of turbine openings or decorative windows 40 (five windowsbeing illustrated) that serve to stylize the wheel 10 or in someapplications provide the function of cooling the brakes (not shown).

The wheel cover or overlay 13 in this preferred embodiment is a solidpanel of a uniform thickness, preferably a high impact, high-temperatureresistant chrome-plated plastic, secured directly to the outboardsurface 32 of the wheel 10. The overlay 13, however, may be made fromany type of material. The wheel includes a pair of rim flanges 11 a (seeFIG. 2B) spaced on opposing sides of the axially extending well 20 overwhich the standard tire is mounted. The rim flanges 11 a circumscribethe wheel disc or web 14 that is welded to the annular rim 11, as is thecase of a standard steel wheel, or integrally cast with the disc, as isthe case of a cast aluminum wheel.

As shown in FIGS. 2B and 2C, an inboard surface 42 of the overlay 13 isconfigured to face the outboard surface 32 of the wheel 10 whenassembled. An opposite or outboard surface 44 of the overlay 13 istherefore visible when the overlay 13 is assembled to the wheel 10. Theoutboard surface 44 of the overlay 13 is adapted to receive a decorativetreatment layer 45. Preferably, a bright metal layer iselectrochemically plated onto the outboard surface of the overlay 13 soas to contribute a bright appearance that adds an aesthetically pleasingappearance to the wheel 10. A painted surface is also contemplated forsome applications. Furthermore, the overlay 13 is preferably formed froma high-impact plastic having an appropriate decorative treatment layer45 on the outboard surface 44 thereof such that the overlay 13 and itsmetal plating are highly resistant to the adverse thermal environment ofthe wheel 10. Alternatively, other high impact and high temperatureresistant plastic overlays or overlays made from any convenient materialare contemplated. As a result, the metal-plated outboard surface of theoverlay 13 can be allowed to redefine the contours of the outboardsurface of the wheel 10, while resisting delamination of the metalplating due to heat or other environmental elements. As shown in FIG.2B, the overlay 13 primarily covers that portion of the outboard surfaceof the wheel 10 formed by the wheel disc 14 inclusive of the rim flange11 c. However, in some applications the overlay does extend to cover theouter lip 11 b of the annular rim 11, as shown in FIG. 2D.

As also shown in FIG. 2C, the wheel 10 further includes a high strength,permanent adhesive sealant 50 that is selectively deposited between theoverlay 13 and the outboard surface 32 of the wheel 10 at the outerdiameter of the overlay and optionally around the turbine openings 40 orinside diameter of the overlay (see FIG. 2B) so as to prevent theingress of water and dirt between the overlay 13 and the wheel 10.Notably, significant portions of the interior of the outboard surfaceare not covered by the adhesive sealant 50, such that large voids 43 arepresent between the overlay 13 and the wheel 10 as a result of theoverlay 13 being axially spaced apart from the outboard surface 32 ofthe wheel for a purpose hereinafter to be disclosed. The adhesivesealant 50 serves as a permanent and primary element for securing theoverlay 13 to the wheel 10. High strength adhesives that are suitablefor use as the adhesive sealant 50 of this invention are known andcommercially available. Because of their high temperature capability anddesirable mechanical properties, silicone and polyurethane adhesives arepreferred. It is, however, foreseeable that other high strength and hightemperature resistive adhesives could be employed with satisfactoryresults. While suitable adhesives for use as the adhesive sealant 50must have excellent mechanical properties, such adhesives are generallycharacterized by relatively slow cure rates that can require severalhours before the adhesive sealant 50 is sufficiently set to absorbsevere impacts or harsh handling without detrimental effects thereto.

Accordingly, through experimentation with various adhesives it has beenfound that by managing the amounts of adhesive and its location it iscontemplated to optimize the cure time. Further, it has been found thatthe use of a UV cure urethane adhesive/sealant significantly reducescure time to a few minutes.

The wheel and overlay configuration illustrated in FIG. 2A is useful forillustrating some of the advantageous aspects of the present invention.A first aspect involves the use of one or more intermediate positivefixing elements for temporarily positioning and securing the overlay 13to the wheel 10 during an interval in which the adhesive sealant 50 isallowed to cure as illustrated in U.S. Pat. No. 5,597,213, owned by theassignee hereof. A second and interrelated aspect of this inventioninvolves the selective placement of the adhesive sealant 50 between theoverlay 13 and the wheel 10 so as to improve the overallmanufacturability, performance, and consumer-perceived quality of theresulting wheel assembly.

In view of the above, it can be seen that the embodiments illustrated inFIGS. 2A through 2D make combinations of overlays and wheels as well asnovel methods for assembling the overlay to a wheel possible. Ingeneral, the method involves temporarily securing an overlay to theoutboard surface 32 of a wheel and applying, in some areas, an adhesivesealant for the purpose of minimizing leakage of a foam adhesive that isinjected between the cladding and wheel so that the overlay will remainpositively positioned on the wheel until the adhesive sealant 50 curescompletely. Accurate placement of an overlay on a wheel is necessary notonly for aesthetic appearances, but also for proper wheel balance. Theembodiments of FIGS. 2A and 2C require the use of equipment and/orfixtures for accurately locating the overlay on the wheel. Notably, theuse of the snap tabs incorporated herein by reference as shown in FIG. 3of U.S. Pat. No. 5,597,213 to Chase and owned by the common assigneehereof are particularly expedient, in that no additional feature isrequired on the wheel in order to accurately locate the overlay. In use,each of the elements illustrated in FIG. 3 of U.S. Pat. No. 5,597,213cause the overlay to be spaced apart from the outboard surface of thewheel so as to define a gap that accommodates the curable adhesivesealant that permanently secures the overlay to the wheel.

The illustrated embodiments are not intended to be limiting. It iscontemplated that other structural elements may be used to center thewheel as well as to accommodate tolerance variations that may result inunacceptable user-perceived aesthetic conditions.

Assembly Process of the Preferred Embodiment

Generally the process of assembly, 100, of the present invention, shownin flow chart form in FIG. 3A and FIG. 3B, involves fixturing anoverlay, 102, applying an adhesive, 104, locating a wheel to theoverlay, 110 and 120, thereby defining a cavity or voids 43therebetween, preheating the overlay/wheel assembly 130, and filling theoverlay/wheel assembly with a foam adhesive 140, 150. There are variousoptional steps and alternatives that will be discussed in detailthroughout this assembly process.

Referring generally to FIGS. 2A through 3B, while the preferred processof assembly 100 teaches the use of an adhesive sealant 50 shown in FIG.2C applied to the overlay 13 prior to locating the overlay 13 to thewheel 10 to serve the stated purposes, the process may be practicedwithout the use of the adhesive sealant 50 disclosed in the preferredembodiment or, alternatively, adhesive sealant 50 may be used on therespective mating surfaces of the wheel 10 and overlay 13 around theturbine openings. It is beneficial to apply the adhesive sealant 50 inareas of the wheel/overlay assembly 10, 13 that are known to squeak,and/or be difficult to seal due to manufacturing tolerances or known tobe subject to entrapment of dirt, mud and/or water. For example, steelwheels sometimes have a rolled rim flange 11 c as shown in FIG. 2B. Itis difficult to assure a true surface at the rolled rim flange 11 c, andit is generally known that foam 60, best shown in FIG. 2C, will leak inthis area. By applying the adhesive sealant 50 around the outer diameterof the wheel prior to filling the wheel/overlay assembly 10, 13 withfoam 60, potential leaks are prevented. Further, to prevent squeaks, thesealant bead may be applied to the wheel 10 or overlay 13 and allowed tofully cure before the overlay 13 is applied to the wheel 10. This hasbeen found to be an effective technique to more efficiently preventsqueaks. The rolled rim flange area 11 c is frequently the first area tofail during durability testing. The additional holding force of theadhesive sealant 50 improves durability results. The adhesive sealant 50is also used to create foam 60 flow patterns by directing the foam flowduring the filling operation.

As stated, while the step of applying an adhesive sealant 50 to theoverlay 13 prior to locating the overlay 13 to the wheel 10 in step 120is not an essential one, it will be discussed as part of this detaileddescription of the preferred embodiment of the present invention.

The overlay 13 is initially oriented in a nest of a fixture with itsoutboard surface 44 facing downward. The overlay 13 is radially locatedoff of either an outer diameter 46 or an inner diameter 47 of theoverlay 13. The overlay 13 is circumferentially located off of either avalve stem opening 48, any turbine opening 40, or a hub opening 49.Finally, the overlay 13 is axially located at the rim flange area 11 cof the outer diameter 46.

After locating and fixturing the overlay 13 in a nest, 102,alternatively, a vacuum may be applied, 103, to assure accurate locationof the overlay in the nest. The vacuum, 103, is not necessary but willreduce warpage, assuring a true surface, i.e., as positioned against thewheel, to which the adhesive sealant 50 is applied, 104. The adhesivesealant 50 is preferably applied by a robot. Locating the overlay, 102,as if it was placed against a wheel surface is essential because it isimportant to apply the adhesive sealant, 104, in a uniform bead along auniform path in order to avoid movement, i.e., droop of the adhesivesealant 50 in subsequent processing before curing, i.e., the overlay ismoved with the fixture so as to be joined to the wheel as will bediscussed hereinafter. The adhesive sealant 50 can be a silicone,urethane, epoxy acrylic or other suitable sealant or adhesive and,alternatively, may be allowed to partially cure, 106, before beingjoined to the wheel.

Locating the wheel, 110, in the fixture is the next step of the process100. If an adhesive sealant 50 is not used, the first step of theprocess 100 is to mount the wheel onto the overlay in the fixture.Depending on the specific application, the wheel may be located axiallyoff of the outboard or inboard surface of the rim flange 11 c; radiallyoff the inside diameter of the rim flange 11 c and/or circumferentiallyoff the valve stem opening 48 or fill hole or, alternatively, balanceout, circumferentially, the plurality of turbine openings 40. The pilotaperture or hub bore 28, bolt pattern 30 and other details (not shown)can also be used as locating features depending on the type of wheelused and how the wheel 10 is manufactured and the relationship of thesefeatures to one another and to the overlay 13.

Referring now to FIG. 6, the overlay 13 is placed outboard side 44 downin a nest of a fixture 70 that locates the wheel 10 to the overlay 13.The wheel is indexed to the fixture 70, inverted and placed on theoverlay. Intermediate attachments and location features canalternatively be used to temporarily clamp the overlay 13 to the wheel10, for example by use of an independent or secondary clamping system72, while the adhesive sealant 50 sets up. It is important to note thatin the preferred embodiment, when the wheel is clamped to the overlay athickness of adhesive sealant must remain between the overlay 13 and thewheel 10 at the rim flange 11 c so that the wheel and overlay do nottouch. This is preferred to avoid any noise, which could be generated asa result of relative movement between the overlay 13 and wheel 10 duringthe life cycle.

In high volume applications, the wheel/overlay assembly 10, 13 is placedon a palletized line. Individual pallets 71 on the palletized line moveindependently through a series of operations. The individual pallets 71are equipped with the independent clamping systems or secondary-clampingsystems 72 that hold the wheel 10 in place on the overlay 13.

Returning to FIGS. 3A and 3B, if an adhesive sealant 50 has been used orhas been partially cured, the wheel/overlay assembly 10, 13 moves to afinal curing station, 122. If no partial cure has occurred and anadhesive sealant was used, the wheel/overlay assembly 10, 13 moves to afinal curing station 124. If no adhesive sealant was used thewheel/overlay assembly 10, 13 goes directly to the preheat station 130.Thereafter, it may undergo heat, humidity or other conditioning. Theconditioning required will be dependent upon the type of adhesivesealant 50 material used. This step is not necessary if an adhesivesealant 50 is not used.

The wheel/overlay assembly 10, 13 is then preheated, 130. It may bepossible to perform this step simultaneously with the curing step whenan adhesive sealant 50 is used. It is desirable for all the surfaces ofthe wheel/overlay assembly 10, 13 to reach a predetermined temperatureof approximately 170° F., depending on the type of adhesive sealantused. Surface temperature affects the foam 60 in a variety of ways,including adhesion, gel, foam initiation time, cohesion, foam fillingcharacteristics, and resultant mechanical properties. The preheattemperature is within the range of 90° F. to 190° F. The preferred rangeis 120° F. to 140° F.

After preheating, 130, the wheel/overlay assembly 10, 13 is transferredto a check station (not shown) where infrared sensors check thetemperature in several pre-determined places. The wheel/overlay assemblyis re-routed to the preheating station if the sensors indicate that theassembly is not at proper preheat temperature. If the proper preheattemperature is sensed, optionally the wheel/overlay assembly may beclamped while the pallet containing the wheel/overlay assembly is routedto the filling station 80 shown schematically in FIG. 5. The fillingstation 80 shown in FIG. 4 and FIG. 5 consists of a lower moving platen82 and an upper platen 84, which constitute the primary clamping system,a foam metering unit 90, and a nest system 95, that will be described indetail below. The filling station 80 is tilted from horizontal to assistliquid foam flow and proper filling of the voids 43.

The wheel/overlay assembly 10, 13 on a palletized system will undergothe following sequence at the filling station 80, as shown in FIG. 3B.The wheel/overlay assembly 10, 13 and pallet 71 enter the fillingstation, 134; the secondary clamping system 72 has already been engaged;the pallet 71 is located and engaged by the lower moving platen 82; andthe lower moving platen 82 rises with the pallet containing thewheel/overlay assembly to engage the upper platen 84 and clamp theassembly securely, 136, in the filling station fixture of the primaryclamping system with the wheel/overlay assembly 10, 13 and the pallet 71secured between the lower moving platen 82 and the upper platen 84. Afirst set of nests 96 of the nest system 95 are engaged, 138, as thepallet 71 is clamped between the lower moving platen 82 and upper platen84 (described in detail below); and a foam injector nozzle 62 seals thefill port and begins to inject the foam, 140, as a result of the fixturebeing tilted from horizontal, the foam flows to the lowest area of thevoids 43 and begins to fill the void from the lowest point towards thehighest area of the voids 43. At about 4 seconds, the foam 60 begins togel. In about 4 seconds the foam 60 liquid starts to foam. The foam 60begins to expand and fill the voids from the lowest point of thewheel/overlay assembly 10, 13 towards the highest point of thewheel/overlay assembly 10, 13, pushing air out of the voids 43 of thewheel/overlay assembly 10, 13. As the foam flow approaches the upperopenings, i.e., turbine openings 40, and center hub opening 49,optionally a second set of nests 97 (also to be described in detailbelow) of the nest system 95 may engage the wheel/overlay assembly 10,13, 142, and sequentially seal each of the turbine openings 40 as thefoam rises. The second set of nests 97 may optionally be vented so thatafter the last turbine opening is sealed, the foam completely seals thevoids or cavities 43 by venting the air through the vent, 144, in thesecond set of nests 97. If the cavity 43 is vented through the nestingsystem 95, it is possible that all nests are applied at the same time sothat the air in the cavity is allowed to vent while the foam fills thecavity 43.

Pressure builds within the cavity 43 between the overlay 13 and thewheel 10 to about 20 psi. The primary clamping system is held closed forabout two minutes (note: if the secondary clamping system 72 discussedabove is not used, the primary clamping system must remain closed for8-10 minutes). Thereafter the first set of nests 96 and second set ofnests 97 are disengaged, 160, (the nest system can be periodicallysprayed with a mold release agent to aid in disengaging the nest system95 from the wheel/overlay assembly 10, 13) and the primary clampingsystem opens, 170. The pallet 71 is thereafter unloaded from the fillstation and placed on the production line and moved to the next station.

The newly foamed wheel/overlay assembly 10, 13 rests for 10 to 15minutes, 180, under light clamping pressure of the secondary clampingsystem 72 as the foam 60 continues to expand slightly. The wheel/overlayassembly 10, 13 is thereafter unclamped, 190, from the pallet 71 andindexed to a station where the pallet is flipped over so that thewheel/overlay assembly 10, 13 is oriented to have the outboard side ofthe wheel 10 facing upward, 195. The wheel/overlay assembly 10, 13 isthen placed back on the pallet and directed to a station that locatesthe low point of the wheel/overlay assembly 10, 13, where a sticker isapplied to identify the low point, 200, for subsequent handling. Aserial identification number is applied, 210, to the wheel/overlayassembly 10, 13, and the wheel/overlay assembly 10, 13 is then inspectedand stacked for shipment, 220.

As stated above, the clamping system of the present invention isdescribed in detail herein with reference to FIGS. 4 and 5. The primaryclamping system of the preferred embodiment consists of the upperstationary platen 84 and the lower moving platen 82 of the fillingstation 80. The primary clamping system provides the necessary holdingforce during the foam filling steps 140, 150 by moving the lower movingplaten 82 towards the upper stationary platen 84 and applying pressurefor a predetermined amount of time. The foam is injected into the cavity43 while the lower moving platen 82 presses the wheel/overlay assembly10, 13 into the upper stationary platen 84.

As discussed earlier, the secondary clamping system 72 can also be usedon the pallets 71, to hold the overlay 13 to the wheel 10 while theadhesive sealant 50 cures. The secondary clamping system 72 is also usedto maintain the necessary clamping force during the lower pressurecuring stages of the foam process. The secondary clamping system 72 canbe as simple as a plurality of mechanical toggle clamps 76, shown inFIG. 4, that sandwich the wheel 10 and overlay 13 to the pallet 71 andthe first set of nests or bottom nests 96. This reduces the time thatthe filling station 80 is utilized. The secondary clamping system 72reduces the clamp time in the filling station 80 from 10 minutes toabout 2 minutes. Because the filling station 80 is an extremely highcapital investment, the secondary clamp system 72 is economical andresults in higher production rates.

As stated above, the nest system 95 will be discussed in detail hereinwith reference to FIG. 4. The nest system 95 has a variety of nests thatserve specific purposes. The nests are made out of a variety ofmaterials depending on their specific purposes. The nests are located onthe top and bottom portion of the platens. Some of the nests can beintegral to the pallet in a palletized line.

The first set of nests 96 includes bottom nests 96 a and a valve stemopening nest 96 b. The bottom nests 96 a generally conform to theoutboard 44 surface of the overlay 13, and seal the hub opening 49 andlug nut openings and their purpose is to support the overlay 13 duringthe high pressure phase of the foam filling of 140, 150. The bottomnests 96 a prevent the overlay 13 from lifting off the wheel 10 when thefoam 60 expands. The bottom nests 96 a are capable of spanning asignificant portion of the overlay 13 without distortion. The bottomnests 96 a can be manufactured using pour-in-place techniques with highdurometer silicone, epoxy or urethane, or the bottom nests 96 a can becast or milled out of aluminum or steel. The valve stem opening nest 96b independently engages, allowing independent movement for locating theoverlay 13 to the wheel 10.

Generally, turbine openings 40 a of the overlay 13 extend slightlythrough an inside periphery of the turbine openings 40 in the wheel asshown in FIG. 2B. This creates a gap between the turbine openings 40, ofthe wheel 10 and the turbine openings 40 a of the overlay 13. Thealignment between the overlay 13 and the wheel 10 varies in alldirections due to individual part manufacturing tolerances and assemblytolerances. The upper nests, including the turbine opening nests 97 a,accommodate these variations because the turbine opening nests 97 a aremade of a soft resilient material such as silicone or urethane that iscapable of being displaced.

The turbine opening nests 97 a are made out of a softer durometermaterial, such as silicone or urethane, to seal the gap between theturbine openings 40 a in the overlay 13 and the wheel 10. The gap variesdue to offset tolerances between the wheel disc 14 and the annular rim11. The center bottom nest 96 a must also accommodate these variations.Thus, a softer nest material, that can be compressed in an axialdirection against the wheel 10 and expand radially creating a sealbetween the overlay 13 and the wheel 10, is used. Not all wheel designswill require a nest in this area because the seal may, alternatively, beaccomplished by applying a bead of adhesive sealant 50 between theoverlay 13 and the wheel 10 about the inner diameter 47 or turbineopenings.

If optional nests are used, these nests are also used to aid venting byengaging in a predetermined sequence at a predetermined time combinedwith the turbine opening nests 97 a after the first set of lower nests96 engage. Venting is necessary to ensure uniform foam flow and adequatefoam quantity as the platens 82, 84 are closed. The first set of nests96 initially seal all of the gaps between the overlay 13 and the wheel10 except for the inner diameter 47. As the liquid foam 60 is injectedinto the cavity 43 between the overlay 13 and the wheel 10, itcirculates around the void or cavity 43 towards the outer diameter 46,begins to gels, and starts to foam in a direction from the lowest pointof the void 43 at the outer diameter 46 towards the inner diameter 47.As the foam 60 advances toward the inner diameter 47, the air in thecavity is forced out of the aperture of the inner diameter 47 and thepilot aperture 28 as well as the turbine openings of the wheel. If theoptional turbine opening nests are used, as the foam 60 nears each ofthe turbine openings each opening is sealed individually until the foamapproaches the inner diameter 47. The pilot aperture and lug boltreceiving holes 30 are thereafter sealed with the bottom nests 96 a thatare timed to engage and seal this final area to be filled, 144. Thissame venting technique can be used with other nests to meet variousdesign conditions. Alternatively, the vents may be contained within theindividual nests so that the cavity can properly vent even if all of thenests are applied at once to define the cavity.

The nest system 95 in combination with the overlay 13 and the wheel 10create a mold in which the foam 60 can be injected and allowed to expandwithin the cavity or void 43.

In another embodiment of the present invention, best shown in FIG. 6,the bottom nests 96 a can be configured to positively locate in thepilot aperture 28 of the wheel hub or the lug bolt receiving holes 30.This can be done by using tapered hardened steel pins 98 in the pilotaperture 28 of the hub or a series of steel pins 98 are placed in thelug bolt receiving holes 30.

The foam metering unit 90 shown in FIG. 5 is employed to accuratelydispense the foam 60. Generally, the foam 60 consists of two components.The foam metering unit 90 includes a control panel 91, polyol andisocyanate mix tanks 92, hydraulic pump 93 a, material feed lines, andthe high pressure dispensing head and foam injector nozzle 62 (shown inFIG. 4). The metering unit 90 can accommodate multiple filling stations80 as shown in FIG. 4.

In one variant of the present invention, the high pressure dispensinghead/foam injector nozzle 62 is mounted on the upper stationary platen84. The foam injector nozzle 62 engages a fill port aligned with thefoam injector nozzle 62 in the wheel 10. Liquid foam is injected throughthe fill port into the wheel/overlay assembly 10, 13 and cavity 43 asearlier set forth.

The present invention provides an improved method of permanentlyattaching an overlay to a wheel disc with an adhesive foam by creating amold of the cavity between the wheel and the overlay using localizednests. The present invention can be used with an overlay and wheelhaving at least one turbine opening, without the need for laborintensive trimming of excess foam, or the additional structure ofsleeves and covers to seal the openings. It is to be understood that thedetailed description and drawings of the present invention do notdescribe the only embodiment of the present invention and, in fact,various modifications are obtainable without departing from the scope ofthe present invention, and should be taken in conjunction with theappended claims.

1-25. (canceled)
 26. An apparatus for permanently attaching an overlay having an outboard surface, an inboard surface, an outer diameter, an inner diameter, a valve stem opening, at least one turbine opening, and a flange area about the outer diameter, to a wheel having an outboard surface on a wheel disc, an outer wheel flange, a rim flange, a valve stem opening, a fill port, at least one turbine opening, a hub bore, and a bolt pattern, said apparatus comprising: a fixture for locating said wheel; first means for clamping said wheel to said overlay, said clamping means being attached to said fixture and locating said overlay to said wheel, said outboard surface of said wheel and said inboard surface of said overlay defining a cavity therebetween; a first set of nests aligned with and contacting said overlay and said wheel, said first set of nests having a bottom nest, a valve stem nest adjacent said bottom nest and at least one turbine opening nest aligned with said at least one turbine opening, said bottom nest generally conforming to said outboard surface of said overlay, said valve stem nest and said at least one turbine opening nest closing off said valve stem opening and said at least one turbine opening; a second set of nests comprising a center bottom nest generally conforming to said inner diameter of said overlay and said bolt pattern of said wheel wherein said second set of nests create a seal by means of expanding radially when compressed in an axial direction against said wheel; a movable pallet positioned under said fixture for locating said overlay to said wheel; first means for clamping said overlay and said wheel to said movable pallet; second means for clamping disposed around said wheel and said movable pallet, said second means for clamping comprising: an upper stationary platen having a fill port, said upper stationary platen contacting a surface of said wheel disc; and a lower moving platen contacting said movable pallet wherein said wheel, said overlay and said movable pallet are clamped between said upper stationary and said lower moving platens of said second means for clamping; and a foam filling station for filling said cavity with a foam material, said foam filling station having a nozzle mounted to said upper stationary platen of said second means for clamping, said nozzle being in communication with said fill port of said wheel.
 27. A process for permanently attaching an overlay having an outboard surface and an inboard surface to a wheel having an outer surface and at least one predefined opening therein, said process comprising the steps of: locating said overlay in a fixture; positioning said wheel on said inboard surface of said overlay defining a cavity between said outer surface of said wheel and said inboard surface of said overlay, said overlay having at least one predefined opening therein, said at least one predefined opening of said wheel peripherally surrounding said at least one predefined opening of said overlay; clamping said overlay and wheel to a pallet; heating said overlay and said wheel to a predetermined temperature; engaging at least one localized nest in said at least one predefined opening of said overlay and said at least one predefined opening of said wheel so as to create a localized area of said cavity between said inboard surface of said overlay and said outer surface of said wheel, whereby a mold is made of said cavity; injecting a foamable liquid in to said cavity; curing said foamable liquid; disengaging said localized nest; and unclamping said wheel and said overlay from said pallet.
 28. The process as claimed in claim 27 further comprising the step of clamping said wheel to said overlay after positioning said wheel on said overlay, said clamping steps defining a cavity between said overlay and said wheel, said cavity having a plurality of openings.
 29. The process as claimed in claim 27 wherein said step of heating said overlay and said wheel further comprises heating said overlay and wheel to a predetermined temperature within the range of 90° F. to 190° F. before said step of injecting said predefined quantity of foamable liquid.
 30. The process as claimed in claim 27 further comprising the step of applying an adhesive sealant to said inboard surface of said overlay before said step of positioning said wheel on said inboard surface of said overlay.
 31. The process as claimed in claim 27 further comprising the steps of: applying a vacuum to said overlay to remove any warpage of said overlay; and applying an adhesive sealant to said inboard surface of said overlay before said step of positioning said wheel on said inboard surface of said overlay.
 32. The process as claimed in claim 27 further comprising the steps of: applying a vacuum to said mold cavity before said step of injecting said foamable liquid; and creating a vacuum in said mold cavity during said steps of injecting said predefined quantity of foamable liquid and holding said mold cavity closed for a predetermined period of time.
 33. A process for permanently attaching an overlay having an outboard surface and an inboard surface to a wheel having an outboard surface and at least one predefined opening therein, said process comprising the steps of: locating said overlay in a fixture; placing said wheel in said fixture and on said inboard surface of said overlay thereby defining a cavity between said outboard surface of said wheel and said inboard surface of said overlay; heating said overlay and said wheel to a predetermined temperature; clamping said overlay and wheel to a pallet; engaging at least one nest with said wheel and said overlay; injecting a foamable liquid into said cavity; and disengaging said at least one nest. 